The rotor is assembled directly on a main alternator shaft, and is constructed with a varnished electrical lamination, windings are made of enameled wire or copper bars and which are fixed to the rotating rectifier bridge.
The stator is manufactured with magnetic lamination. The number of poles defines the frequency of exit (between 4 and 80 poles, according to the nominal RPM of the main alternator).
Low speeds from 100 to 1800 RPM, for hydraulic applications or diesels.
High speeds from 3000 to 3600 RPM, for turbo alternators.